American Standard Flash Shower Rough-In Valve With PEX Inlet Elbows/Universal Outlets for Cold Expansion System - AMS-RU108E

The cartridge is not in the box with the RU108E rough-in valve body. It ships with the trim kit instead, so you need to order the matching Flash trim to get a working shower. What you get here is the DZR brass valve body with PEX inlet elbows, the flush plug and test cap arrangement, the stainless retaining ring, and the plaster guard, which is everything needed to rough in and pressure test the wall before the finish work.

Inlets are 1/2 inch PEX cold expansion elbows built to ASTM F1960, so they take F1960 expansion rings and an expansion tool. No adaptors or sweat fittings are needed, which cuts out two leak points per side. Outlets are universal. If your job is crimp or clamp PEX rather than cold expansion, this is the wrong version of the valve.

Rough-in range runs 1-3/4 inches to 2-3/4 inches measured from the finished wall to the back of the valve. That one inch of tolerance covers most stud-wall builds with tile or backer board thickness variation. The flat back lets the body sit tight against a cross brace, and the plaster guard doubles as mounting support on thin-wall installs.

Yes, and that is the point of the flush plug. You test and flush with the plug in place, no cartridge required, and there is no cross flow between hot and cold while you do it. Rated to 200 psi with air or 300 psi with water. The stainless retaining ring holds the test cap without screws, and the flats on it let you spin it loose by hand when it is time to drop the cartridge in.

It will. The RU108E body is symmetrical and can be rotated 180 degrees, so you can feed it from above or below without a different part number. Hot and cold can also be swapped for back-to-back installations, which matters on stacked bathrooms in multi-family work where the plumbing wall is shared.

The body is cast DZR brass, dezincification resistant, specifically for water with high chloride content or elevated pH. That is the material spec property managers should be looking for in coastal buildings or anywhere the municipal supply is aggressive, since standard brass in those conditions is what causes pinhole failures inside the wall.

No, one is included. The plaster guard protects the valve through drywall, mud and tile work and acts as a depth guide while you set the body. On thin-wall installations it also serves as mounting support, which saves fabricating blocking behind a shallow cavity.